Compressor

ABSTRACT

To reduce or prevent failures due to contamination, such as control and/or lubrication failure, the compressor according to the present invention includes an oil separator 230 having a separation portion configured to separate lubricating oil OIL from a working fluid by using a centrifugal force, and a storage portion located below the separation portion and configured to store lubricating oil OIL separated by the separation portion. A hat-shaped trap member 260 is disposed between the separation portion and the storage portion. The trap member 260 allows precipitation and trapping of the contamination CON mixed in the lubricating oil OIL by temporarily storing the lubricating oil OIL separated by the separation portion and discharging a supernatant of the lubricating oil OIL into the storage portion.

TECHNICAL FIELD

The present invention relates to a compressor which compresses a working fluid such as a refrigerant.

BACKGROUND ART

In a compressor, if the refrigerant gas (gaseous refrigerant) compressed by the compression mechanism contains a mist of lubricating oil, this lubricating oil mist may be introduced into the condenser of the refrigerant circuit or the like and may reduce the efficiency of the compressor. To avoid this, the compressor is provided with an oil separator for separating the lubricating oil from the gaseous refrigerant discharged from the compression mechanism. The lubricating oil separated by the oil separator is used for, for example, generating a back pressure which presses the orbiting scroll against the fixed scroll in the scroll compressor. This back pressure is adjusted using a back pressure control valve configured to operate in accordance with a differential pressure between the suction pressure and the discharge pressure.

The lubricating oil of the compressor may contain contamination (foreign matter) such as sludge. When contamination is introduced to the back pressure control valve, the valve element of the back pressure control valve may no longer move smoothly, for example, and the back pressure control valve may become unable to properly adjust the back pressure. To address this situation, conventionally, as disclosed in JP 2003-343433 A (Patent Document 1), a filter is attached to the back pressure control valve so as to trap contamination and reduce or prevent operation failure of the back pressure control valve.

REFERENCE DOCUMENT LIST Patent Document

-   Patent Document 1: JP 2003-343433 A

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

However, the filter of the back pressure control valve has a smaller contamination trap area size. Thus, after the compressor is used for many years, the entire filter surface may be covered with contamination and become unable to allow the lubricating oil to pass therethrough, and this may cause back pressure control failure, lubrication failure at sliding portions, and/or the like. Furthermore, failure due to contamination in the lubricating oil may occur not only in the back pressure control valve but also in other components such as the orifice disposed in the lubricating oil flow path.

Therefore, an object of the present invention is to provide a compressor in which failures due to contamination, such as control and/or lubrication failure, can be reduced or prevented.

Means for Solving the Problem

To this end, the compressor according to the present invention includes an oil separator having a separation portion configured to separate lubricating oil from a working fluid by using a centrifugal force, and a storage portion located below the separation portion and configured to store lubricating oil separated by the separation portion. Between the separation portion and the storage portion, a trap member configured to temporarily store the lubricating oil separated by the separation portion and to discharge a supernatant of the lubricating oil into the storage portion is disposed.

Effects of the Invention

According to the present invention, failures due to contamination, such as control and/or lubrication failure, can be reduced or prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an example of a scroll compressor.

FIG. 2 is a drawing for illustrating how lubricating oil is separated by an oil separator.

FIG. 3 is a block diagram for illustrating the flows of refrigerant and lubricating oil.

FIG. 4 is a vertical cross-sectional view of a first embodiment of a trap member.

FIG. 5 is a vertical cross-sectional view of a substantial part of a modification of the trap member according to the first embodiment.

FIG. 6 is a vertical cross-sectional view of a second embodiment of the trap member.

FIG. 7 is a vertical cross-sectional view of a third embodiment of the trap member.

FIG. 8 is a vertical cross-sectional view of a substantial part of a modification of the trap member according to the third embodiment.

MODES FOR CARRYING OUT THE INVENTION

Embodiments for implementing the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an example of a scroll compressor. The scroll compressor is an example of a compressor.

A scroll compressor 100 includes a scroll unit 120, a housing 140 having a suction chamber H1 and a discharge chamber H2 for gaseous refrigerant, an electric motor 160 for driving the scroll unit 120, and an inverter 180 for controlling the electric motor 160. The scroll unit 120 may be driven by, for example, an engine output instead of by the electric motor 160. The inverter 180 does not have to be incorporated in the scroll compressor 100.

The scroll unit 120 has a fixed scroll 122 and an orbiting scroll 124 engaged with each other. The fixed scroll 122 includes a disk-shaped bottom plate 122A and an involute-shaped (spiral-shaped) wrap 122B that is erected from one surface of the bottom plate 122A. Like the fixed scroll 122, the orbiting scroll 124 also includes a disk-shaped bottom plate 124A and an involute-shaped wrap 124B that is erected from one surface of the bottom plate 124A.

The fixed scroll 122 and the orbiting scroll 124 are disposed such that the wraps 122B and 124B are engaged with each other. Specifically, the fixed scroll 122 and the orbiting scroll 124 are disposed such that the tip of the wrap 122B of the fixed scroll 122 is in contact with the one surface of the bottom plate 124A of the orbiting scroll 124, and the tip of the wrap 124B of the orbiting scroll 124 is in contact with the one surface of the bottom plate 122A of the fixed scroll 122. A tip seal (not shown) is attached to each of the tips of the wraps 122B and 124B.

Furthermore, the fixed scroll 122 and the orbiting scroll 124 are disposed such that the circumferential angles of the wraps 122B and 124B are offset from each other and the sidewalls of the wraps 122B and 124B are partially in contact with each other. As a result, a crescent-shaped sealed space functioning as a compression chamber H3 is formed between the wrap 122B of the fixed scroll 122 and the wrap 124B of the orbiting scroll 124.

The orbiting scroll 124 is disposed so as to be orbitable about the axis of the fixed scroll 122 via a crank mechanism 240 which will be described later, in a state in which rotation of the orbiting scroll 124 is prevented. Thus, the scroll unit 120 moves the compression chamber H3 defined by the wrap 122B of the fixed scroll 122 and the wrap 124B of the orbiting scroll 124 toward the center while gradually reducing the volume of the compression chamber H3. As a result, the scroll unit 120 compresses the gaseous refrigerant drawn from the outer ends of the wraps 122B and 124B into the compression chamber H3.

The housing 140 has a front housing 142 for housing the electric motor 160 and the inverter 180, a center housing 144 for housing the scroll unit 120, a rear housing 146, and an inverter cover 148. The front housing 142, the center housing 144, the rear housing 146 and the inverter cover 148 are integrally fastened by, for example, at least one fastener (not shown) including a bolt and a washer, so as to constitute the housing 140 of the scroll compressor 100.

The front housing 142 has a peripheral wall portion 142A having a substantially cylindrical shape and a partition wall portion 142B. The internal space of the front housing 142 is divided by the partition wall portion 142B into two spaces: one for housing the electric motor 160 and the other for housing the inverter 180. An opening at one end of the peripheral wall portion 142A is closed by the inverter cover 148. An opening at the other end of the peripheral wall portion 142A is closed by the center housing 144. A substantially cylindrical support portion 142B1 protruding toward the other end of the peripheral wall portion 142A is provided at a radially center portion of the partition wall portion 142B. The support portion 142B1 rotatably supports one end of a drive shaft 166, which will be described later.

Furthermore, the suction chamber H1 for gaseous refrigerant is defined by the peripheral wall portion 142A and the partition wall portion 142B of the front housing 142 and the center housing 144. Low-pressure, low-temperature gaseous refrigerant is drawn into the suction chamber H1 through a suction port P1 formed in the peripheral wall portion 142A. The suction chamber H1 is adapted to allow gaseous refrigerant to flow around the electric motor 160 and cool the electric motor 160, and spaces on opposite sides of the electric motor 160 communicate with each other so as to form the single suction chamber H1. An appropriate amount of lubricating oil is stored in the suction chamber H1 in order to lubricate sliding portions of components such as the drive shaft 166, which is rotationally driven. Accordingly, gaseous refrigerant flows in the suction chamber H1 in the form of a mixed fluid with a lubricating oil.

The center housing 144 has a substantially bottomed cylindrical shape that is open on the side opposite to the side fastened to the front housing 142 and is adapted to house the scroll unit 120 therein. The center housing 144 has a cylindrical portion 144A and a bottom wall portion 144B provided at one end of the cylindrical portion 144A. The scroll unit 120 is housed in a space defined by the cylindrical portion 144A and the bottom wall portion 144B. At the other end of the cylindrical portion 144A, a fitting portion 144A1 to which the fixed scroll 122 is fitted is formed. Accordingly, the opening of the center housing 144 is closed by the fixed scroll 122. The bottom wall portion 144B is formed such that a radially center portion thereof bulges toward the electric motor 160. A through hole for receiving the other end of the drive shaft 166 passing therethrough is formed at the radially center portion of such a bulging portion 144B1 of the bottom wall portion 144B. Furthermore, a fitting portion for receiving a bearing 200 fitted therein is formed on the side, closer to the scroll unit 120, of the bulging portion 144B1. The bearing 200 rotatably supports the other end of the drive shaft 166.

An annular thrust plate 210 is disposed between the bottom wall portion 144B of the center housing 144 and the bottom plate 124A of the orbiting scroll 124. The bottom wall portion 144B receives, at an outer peripheral portion, a thrust force from the orbiting scroll 124 via the thrust plate 210. Seal members (not shown) are embedded in respective portions, in contact with the thrust plate 210, of the bottom wall portion 144B and the bottom plate 124A.

A back pressure chamber H4 is formed between the bottom wall portion 144B and the end surface, facing the electric motor 160, of the bottom plate 124A; that is, between the center housing 144 and the end surface, opposite to the fixed scroll 122, of the orbiting scroll 124. The center housing 144 is provided with a refrigerant introduction passage L1 formed so as to introduce gaseous refrigerant (specifically, a mixed fluid of the gaseous refrigerant and lubricating oil) from the suction chamber H1 to a space H5 near the outer ends of the wraps 122B and 124B of the scroll unit 120. Since the refrigerant introduction passage L1 communicates the space H5 with the suction chamber H1, the pressure in the space H5 is equal to the pressure (suction pressure Ps) in the suction chamber H1.

The rear housing 146 is fastened to an end, closer to the fitting portion 144A1, of the cylindrical portion 144A of the center housing 144 with at least one fastener. Accordingly, the fixed scroll 122 is fixed to the housing 140 with the bottom plate 122A held between the fitting portion 144A1 and the rear housing 146. The rear housing 146, which has a substantially bottomed cylindrical shape having an opening at a side fastened to the center housing 144 (at one end), has a cylindrical portion 146A and a bottom wall portion 146B provided at the other end of the cylindrical portion 146A.

The discharge chamber H2 for gaseous refrigerant is defined by the cylindrical portion 146A and the bottom wall portion 146B of the rear housing 146 and the bottom plate 122A of the fixed scroll 122. A discharge passage (discharge hole) L2 for compressed refrigerant is formed at a central portion of the bottom plate 122A. The discharge passage L2 is provided with a check valve 220 formed of, for example, a reed valve. The check valve 220 restricts the flow from the discharge chamber H2 to the scroll unit 120. Refrigerant having been compressed in the compression chamber H3 of the scroll unit 120 is discharged to the discharge chamber H2 through the discharge passage L2 and the check valve 220.

An oil separator 230 is disposed in the rear housing 146. The oil separator 230 is configured to separate lubricating oil from the gaseous refrigerant in the discharge chamber H2. Specifically, a gas-liquid separation chamber 230A is formed at the rear end, i.e., at the end opposite to the center housing 144, of the rear housing 146. The gas-liquid separation chamber 230A has a circular transverse cross section and extends inwardly from the outer peripheral wall of the rear housing 146. In the gas-liquid separation chamber 230A, a step-shaped inner cylinder 230B having a circular transverse cross section is inserted coaxially with the gas-liquid separation chamber 230A. The inner cylinder 230B has a base end portion engaged with a step portion 230A1 of the gas-liquid separation chamber 230A, and a distal end extending to a location spaced a predetermined distance from the deepest position of the gas-liquid separation chamber 230A. Here, a space, in which at least the inner cylinder 230B exists, of the gas-liquid separation chamber 230A functions as a separation portion configured to separate the lubricating oil from the gaseous refrigerant. On the other hand, a substantially columnar space located at the deepest position of the gas-liquid separation chamber 230A below the separation portion functions as a storage portion for temporarily storing the lubricating oil separated by the oil separator 230.

The opening of the gas-liquid separation chamber 230A in the rear housing 146 is closed by a bolt (not shown) capable of pressing the inner cylinder 230B. The bolt has a through hole formed to penetrate through the bolt from the end surface of the bolt head to the distal end of the bolt shank. The bolt head has a discharge port P2 for pipe connection, which is formed to guide, to the condenser (not shown), the gaseous refrigerant from which the lubricating oil has been separated by the oil separator 230. Furthermore, the gas-liquid separation chamber 230A is in communication with the discharge chamber H2 through an introduction port 146C extending tangentially to the inner peripheral surface of the gas-liquid separation chamber 230A.

Therefore, the gaseous refrigerant compressed by the scroll unit 120 is introduced into the discharge chamber H2 and then into the oil separator 230 through the introduction port 146C. As shown in FIG. 2, the gaseous refrigerant introduced into the oil separator 230 spirals downward in an annular space defined by the inner peripheral surface of the gas-liquid separation chamber 230A and the outer peripheral surface of the inner cylinder 230B. In this event, a mist of lubricating oil contained in the gaseous refrigerant is moved outward by the centrifugal force generated by the spiral motion of the gaseous refrigerant. After being moved outward, the lubricating oil mist adheres to the inner peripheral surface of the gas-liquid separation chamber 230A, and is then dropped down to the bottom of the gas-liquid separation chamber 230A by gravity. Then, the lubricating oil separated by the oil separator 230 is introduced into a pressure supply passage L3, which will be described later. Meanwhile, the gaseous refrigerant from which the lubricating oil has been separated enters the internal space of the inner cylinder 230B from the distal end thereof, and is discharged by the pressure of the internal space through the discharge port P2 formed in the bolt head.

In FIG. 1, the flow of the gaseous refrigerant before being mixed with the lubricating oil or after being separated from the lubricating oil is indicated by the hatched arrows. The flow of the gaseous refrigerant mixed with the lubricating oil (flow of the mixed fluid) is indicated by the solid arrows. The flow of the lubricating oil that has been separated from the gaseous refrigerant is indicated by the unfilled arrows.

The electric motor 160 is, for example, a three-phase alternating current motor, and includes a rotor 162 and a stator core unit 164 disposed radially outward of the rotor 162. The electric motor 160 is supplied with an alternating current to which a direct current from, for example, an in-vehicle battery (not shown) is converted by the inverter 180.

The rotor 162 is disposed radially inside the stator core unit 164 and rotatably supported on the drive shaft 166 that is press-fitted into an axial hole formed at the radial center of the rotor 162. One end of the drive shaft 166 is rotatably supported on the support portion 142B1 of the front housing 142. The other end of the drive shaft 166 passes through the through hole formed in the center housing 144 and is rotatably supported on the bearing 200. When a current is supplied to the electric motor 160 by the inverter 180, a magnetic field is generated in the stator core unit 164 and a torque acts on the rotor 162 to rotationally drive the drive shaft 166. The other end of the drive shaft 166 is connected to the orbiting scroll 124 via the crank mechanism 240.

The crank mechanism 240 has a substantially cylindrical boss portion 240A and an eccentric bushing 240C. The boss portion 240A is formed protruding from an end surface, facing the back pressure chamber H4, of the bottom plate 124A of the orbiting scroll 124. The eccentric bushing 240C is eccentrically mounted to a crank 240B provided at the other end of the drive shaft 166. The eccentric bushing 240C is rotatably supported by the boss portion 240A. At the other end of the drive shaft 166, a balancer weight 240D for balancing the centrifugal force caused by the operation of the orbiting scroll 124 is attached. Accordingly, the orbiting scroll 124 is orbitable about the axis of the fixed scroll 122 via the crank mechanism 240 in a state in which rotation of the orbiting scroll 124 is restricted. Here, the scroll unit 120, the drive shaft 166, and the crank mechanism 240 is an example of a compression mechanism.

FIG. 3 is a block diagram for illustrating the flows of the refrigerant and the lubricating oil in the scroll compressor 100.

As shown in FIGS. 1 and 3, the low-pressure, low-temperature gaseous refrigerant from the evaporator is introduced into the suction chamber H1 through the suction port P1, and then introduced into the space H5 near the outer end of the scroll unit 120 through the refrigerant introduction passage L1. The gaseous refrigerant in the space H5 is taken into the compression chamber H3 of the scroll unit 120 and compressed therein. After being compressed in the compression chamber H3, the refrigerant is discharged into the discharge chamber H2 through the discharge passage L2 and the check valve 220, and then introduced from the discharge chamber H2 to the oil separator 230 through the introduction port 146C. The gaseous refrigerant from which the lubricating oil has been separated by the oil separator 230 is discharged to the condenser through the discharge port P2. In this way, the scroll unit 120 is configured to compress, in the compression chamber H3, the gaseous refrigerant flowing therein via the suction chamber H1 and discharge the compressed refrigerant via the discharge chamber H2.

As shown in FIG. 1, a back pressure control valve 250 for pressure adjustment of the back pressure chamber H4 is further incorporated at the rear end of the rear housing 146.

The back pressure control valve 250, which is a well-known mechanical (autonomous) flow rate control valve, operates in accordance with the suction pressure Ps of the suction chamber H1 and the discharge pressure Pd of the discharge chamber H2 and thereby automatically adjusts the valve opening so as to bring the back pressure Pm of the back pressure chamber H4 closer to a target back pressure Pc that varies depending on the suction pressure Ps and the discharge pressure Pd.

As shown in FIGS. 1 and 3, the scroll compressor 100 includes the pressure supply passage L3 and a pressure release passage L4 in addition to the refrigerant introduction passage L1 and the discharge passage L2.

The back pressure control valve 250 is disposed in a middle portion of the pressure supply passage L3 so as to constitute a part of the pressure supply passage L3. Accordingly, the lubricating oil separated by the oil separator 230 is supplied to the back pressure chamber H4 after being appropriately decompressed by the back pressure control valve 250 while passing through the pressure supply passage L3. That is, by using the back pressure control valve 250 to adjust the opening of the pressure supply passage L3 connected to the inlet side (upstream side) of the back pressure chamber H4, the flow rate of the lubricating oil entering the back pressure chamber H4 is increased or decreased, and thus, the back pressure Pm is adjusted.

The pressure release passage L4 communicates the back pressure chamber H4 with the suction chamber H1. An orifice OL is disposed in a middle portion of the pressure release passage L4. The pressure release passage L4 provided with the orifice OL is formed so as to pass through the drive shaft 166 and extend along the central axis of the drive shaft 166. The orifice OL is disposed at the end, closer to the suction chamber H1, of the drive shaft 166, for example. The lubricating oil in the back pressure chamber H4 is returned to the suction chamber H1 at a flow rate restricted by the orifice OL.

The orbiting scroll 124 is pressed against the fixed scroll 122 by the back pressure Pm of the back pressure chamber H4. Assume here the case in which the scroll unit 120 performs compression operation in a state in which the resultant force of the back pressure Pm acting on the end surface, facing the back pressure chamber H4, of the bottom plate 124A of the orbiting scroll 124 is smaller than the compression reaction force acting on the end surface, facing the compression chamber H3, of the bottom plate 124A; that is, the scroll unit 120 performs compression operation with an insufficient back pressure. In such a case, a gap may be created between the tip of the wrap 124B of the orbiting scroll 124 and the bottom plate 122A of the fixed scroll 122 and a gap may be created between the bottom plate 124A of the orbiting scroll 124 and the tip of the wrap 122B of the fixed scroll 122. These gaps may reduce the volumetric efficiency of the compressor. To avoid this, the back pressure control valve 250 adjusts the back pressure Pm such that its resultant force is greater than the compression reaction force.

On the other hand, however, if the resultant force of the back pressure Pm in the back pressure chamber H4 is excessively higher than the compression reaction force; that is, if the back pressure is excessive, the frictional force between the fixed scroll 122 and the orbiting scroll 124 will excessively increase and reduce the machine efficiency of the compressor. To avoid this, when the back pressure Pm exceeds the target back pressure Pc, the back pressure control valve 250 reduces the back pressure Pm closer to the target back pressure Pc in order to avoid excessive back pressure.

Here, the lubricating oil separated by the oil separator 230 still contains contamination such as sludge. When contamination is introduced to the back pressure control valve 250 located downstream of the oil separator 230, the valve element of the back pressure control valve 250 may no longer move smoothly, for example, and the back pressure control valve 250 may become unable to adjust the back pressure Pm in the back pressure chamber H4 closer to the target back pressure Pc. When contamination is introduced to the orifice OL located downstream of the oil separator 230, the contamination may close or narrow the flow path for the lubricating oil, for example, and it may become difficult to return the lubricating oil from the back pressure chamber H4 to the suction chamber H1. As a result, the back pressure control valve 250 may become unable to adjust the back pressure Pm in the back pressure chamber H4 closer to the target back pressure Pc.

To address the above, the oil separator 230 further includes a trap member for precipitating and trapping contamination mixed in the lubricating oil. The trap member is disposed between the separation portion and the storage portion, and configured to temporarily store the lubricating oil separated by the separation portion and to discharge the supernatant of the lubricating oil into the storage portion.

FIG. 4 shows a first embodiment of the trap member for trapping contamination.

A trap member 260 is formed of a hat-shaped partition wall and disposed between the distal end of the inner cylinder 230B and the bottom wall of the gas-liquid separation chamber 230A. The trap member 260 includes an annular portion 262 having a thin annular shape, a cylindrical portion 264 having a cylindrical shape rising from the inner circumferential edge of the annular portion 262, and a disk portion 266 having a disk shape and closing the upper opening of the cylindrical portion 264. Here, the cylindrical portion 264 is an example of a portion rising toward the separation portion.

The outer circumferential edge of the annular portion 262 is fixed onto the inner peripheral surface of the gas-liquid separation chamber 230A along a transverse cross section thereof. Furthermore, the cylindrical portion 264 has a plurality of small holes 264A which communicate the inner and outer peripheral surfaces of the cylindrical portion 264 with each other along a transverse cross section of the cylindrical portion 264. The opening area of each small hole 264A is appropriately determined so as to allow the lubricating oil to pass therethrough, in consideration of, for example, the viscosity of the lubricating oil. The positions of the small holes 264A are appropriately determined in consideration of, for example, how much volume of the lubricating oil should be trapped. Note that the disk portion 266 is not limited to one having a flat surface, and may have a surface having an upwardly protruding center portion, such as a partial spherical surface or a conical surface.

With the trap member 260, the lubricating oil OIL that is dropped down after being adhered to the inner peripheral surface of the gas-liquid separation chamber 230A is received by the substantially annular region defined by the inner peripheral surface of the gas-liquid separation chamber 230A, the upper surface of the annular portion 262, and the outer peripheral surface of the cylindrical portion 264. The lubricating oil OIL received in this region is discharged to the lower portion, which functions as the storage portion, of the gas-liquid separation chamber 230A through the small holes 264A of the cylindrical portion 264. While the lubricating oil OIL is temporarily received in the substantially annular region, the supernatant of the lubricating oil OIL is discharged to the lower portion of the gas-liquid separation chamber 230A through the small holes 264A of the cylindrical portion 264. In this way, the trap member 260 allows precipitation and trapping of the contamination CON mixed in the lubricating oil OIL.

As a result, less contamination is introduced into the back pressure control valve 250 and the orifice OL located downstream of the oil separator 230. Accordingly, control and/or lubrication failure due to contamination is reduced or prevented and the durability of the scroll compressor 100 can be improved. Minor contamination left uncollected by the oil separator 230 is discharged to the outside together with the gaseous refrigerant and trapped by, for example, a receiver drier disposed in the refrigerant circuit.

A part of the lubricating oil dropped into the substantially annular region may be disturbed upward by the spiral flow of the gaseous refrigerant spiraling down around the outer periphery of the inner cylinder 230B and may be taken into the inner cylinder 230B from its distal end. To mitigate such upward disturbance of the lubricating oil, a flange portion 268 having a thin disk shape may be formed integrally to an upper portion of the trap member 260, specifically, on the outer circumferential edge of the disk portion 266, as shown in FIG. 5. With this configuration, even when the lubricating oil is partially disturbed upward by the spiral flow, the disturbed flow hits the lower surface of the flange portion 268 and is redirected back downward. Thus, the above configuration reduces the absolute amount of the lubricating oil that is taken into the inner cylinder 230B from its distal end. Note that the flange portion 268 may also be provided to any of the trap members described below.

FIG. 6 shows a second embodiment of the trap member for trapping contamination.

A trap member 270 is formed of a hat-shaped partition wall and disposed between the distal end of the inner cylinder 230B and the bottom wall of the gas-liquid separation chamber 230A. The trap member 270 includes an annular portion 272 having a thin annular shape with a radially center portion protruding downward, a conical portion 274 having a truncated conical shape rising from the inner circumferential edge of the annular portion 272, and a disk portion 276 having a disk shape with a radially center portion protruding upward and closing the upper opening of the conical portion 274. Here, the conical portion 274 is an example of the portion rising toward the separation portion.

The outer circumferential edge of the annular portion 272 is fixed onto the inner peripheral surface of the gas-liquid separation chamber 230A along a transverse cross section thereof. Furthermore, the conical portion 274 has a plurality of small holes 274A which communicate the inner and outer peripheral surfaces of the conical portion 274 with each other along a transverse cross section of the conical portion 274. The opening area of each small hole 274A is appropriately determined so as to allow the lubricating oil to pass therethrough, in consideration of, for example, the viscosity of the lubricating oil. The positions of the small holes 264A are appropriately determined in consideration of, for example, how much volume of the lubricating oil should be trapped.

With the trap member 270, the lubricating oil OIL that is dropped down after being adhered to the inner peripheral surface of the gas-liquid separation chamber 230A is received at least on the upper surface of the annular portion 272, which has the radially center portion protruding downward. The lubricating oil received by the annular portion 272 is discharged to the lower portion, which functions as the storage portion, of the gas-liquid separation chamber 230A through the small holes 274A of the conical portion 274. While the lubricating oil OIL is temporarily received in the annular portion 272, the supernatant of the lubricating oil OIL is discharged to the lower portion of the gas-liquid separation chamber 230A through the small holes 274A of the conical portion 274. In this way, the trap member 270 allows precipitation and trapping of the contamination CON mixed in the lubricating oil OIL.

As a result, less contamination is introduced into the back pressure control valve 250 and the orifice OL located downstream of the oil separator 230, as in the first embodiment. Accordingly, control and/or lubrication failure due to contamination is reduced or prevented and the durability of the scroll compressor 100 can be improved. Note that the trap member 270 does not have to include the conical portion 274 and the outer circumferential edge of the disk portion 276 may be directly connected to the inner circumferential edge of the annular portion 272. In this case, a plurality of small holes adapted to allow the lubricating oil to flow therethrough may be formed in at least one of the annular portion 272 and the disk portion 276, and the portion with these small holes is an example of the portion rising toward the separation portion.

FIG. 7 shows a third embodiment of the trap member for trapping contamination.

A trap member 280 is formed as a partition wall having a shape described below and disposed between the distal end of the inner cylinder 230B and the bottom wall of the gas-liquid separation chamber 230A. The trap member 280 includes an annular portion 282 having a thin annular shape, a cylindrical portion 284 having a cylindrical shape rising from the inner circumferential edge of the annular portion 282, and a flange portion 286 having a thin annular shape extending radially outward from the upper end of the cylindrical portion 284. Here, the cylindrical portion 284 is an example of the portion rising toward the separation portion.

The outer circumferential edge of the annular portion 282 is fixed onto the inner peripheral surface of the gas-liquid separation chamber 230A along a transverse cross section thereof. Furthermore, the cylindrical portion 284 has a plurality of small holes 284A which communicate the inner and outer peripheral surfaces of the cylindrical portion 284 with each other along a transverse cross section of the cylindrical portion 284. The opening area of each small hole 284A is appropriately determined so as to allow the lubricating oil to pass therethrough, in consideration of, for example, the viscosity of the lubricating oil. The positions of the small holes 284A are appropriately determined in consideration of, for example, how much volume of the lubricating oil should be trapped. Like the flange portion 268 shown in FIG. 5, the flange portion 286 also mitigates upward disturbance of a part of the lubricating oil received by the trap member 280.

With the trap member 280, the lubricating oil OIL that is dropped down after being adhered to the inner peripheral surface of the gas-liquid separation chamber 230A is received by the substantially annular region defined by the inner peripheral surface of the gas-liquid separation chamber 230A, the upper surface of the annular portion 282, and the outer peripheral surface of the cylindrical portion 284. The lubricating oil OIL received in this region is discharged to the lower portion, which functions as the storage portion, of the gas-liquid separation chamber 230A through the small holes 284A of the cylindrical portion 284. While the lubricating oil OIL is temporarily received in the substantially annular region, the supernatant of the lubricating oil OIL is discharged to the lower portion of the gas-liquid separation chamber 230A through the small holes 284A of the cylindrical portion 284. In this way, the trap member 280 allows precipitation and trapping of the contamination CON mixed in the lubricating oil OIL.

Furthermore, since the upper end opening of the cylindrical portion 284 is not closed, the trap member 280 may include fewer components and have a weight reduced accordingly. Here, the lubricating oil OIL is dropped down along the inner peripheral surface of the gas-liquid separation chamber 230A. Thus, even though the upper end opening of the cylindrical portion 284 is not closed, the lubricating oil OIL is unlikely to be dropped down directly to the lower portion of the gas-liquid separation chamber 230A through the upper end opening of the cylindrical portion 284. Here, the upper end opening of the cylindrical portion 284 is an example of a communication hole which communicates the separation portion with the storage portion.

As a result, less contamination is introduced into the back pressure control valve 250 and the orifice OL located downstream of the oil separator 230, as in the first and second embodiments. Accordingly, control and/or lubrication failure due to contamination is reduced or prevented and the durability of the scroll compressor 100 can be improved. Note that the flange portion 286 may be omitted when the lubricating oil is unlikely to be partially disturbed upward.

FIG. 8 shows a modification of the trap member.

A trap member 290 according to the modification includes a conical portion 292 having a truncated conical shape formed so that its transverse cross-sectional area decreases upward, and a flange portion 294 having a thin annular shape extending radially outward from the upper end of the conical portion 292. Here, a middle section of the conical portion 292 is an example of the portion rising toward the separation portion. The outer circumferential edge of the lower end of the conical portion 292 is fixed onto the inner peripheral surface of the gas-liquid separation chamber 230A. Furthermore, the conical portion 292 has a plurality of small holes 292A which communicate the inner and outer peripheral surfaces of the conical portion 292 with each other along a transverse cross section of the conical portion 292.

The lubricating oil OIL that is dropped down along the inner peripheral wall of the gas-liquid separation chamber 230A is received by the substantially annular region defined by the inner peripheral surface of the gas-liquid separation chamber 230A and the outer peripheral surface of the conical portion 292. The lubricating oil OIL received in this region is discharged to the lower portion, which functions as the storage portion, of the gas-liquid separation chamber 230A through the small holes 292A of the conical portion 292. The trap member 290 provides operational advantages and effects similar to those described in the first to third embodiments. Thus, description therefor will be omitted to avoid redundant description. Please also refer to the above description, if necessary.

As described above, the trap member for trapping contamination mixed in the lubricating oil may have various shapes. In other words, the trap member may have any shape as it is functionally shaped so as at least to temporarily store the lubricating oil separated by the separation portion and discharge the supernatant of the lubricating oil into the storage portion. If, as in the prior art, the back pressure control valve 250 is provided with a filter, the filter will not be clogged in a short time since a reduced absolute amount of contamination is introduced into the back pressure control valve 250.

In the above embodiments, the compressor is assumed to be a scroll compressor. However, the compressor may be a reciprocating compressor, a swash plate compressor, a rotary piston compressor, a slide vane compressor, or the like. Furthermore, the oil separator is not limited to a centrifugal oil separator and may be configured, for example, to use a labyrinth passage to separate lubricating oil from gaseous refrigerant.

REFERENCE SYMBOL LIST

-   100 Scroll compressor (Compressor) -   230 Oil separator -   260 Trap member -   264 Cylindrical portion -   264A Small hole -   268 Flange portion -   270 Trap member -   274 Conical portion -   274A Small hole -   280 Trap member -   284 Cylindrical portion -   284A Small hole -   286 Flange portion -   290 Trap member -   292 Conical portion -   292A Small hole -   294 Flange portion -   OIL Lubricating oil 

1. A compressor comprising an oil separator having: a separation portion configured to separate lubricating oil from a working fluid by using a centrifugal force; and a storage portion located below the separation portion and configured to store lubricating oil separated by the separation portion, wherein a trap member configured to temporarily store the lubricating oil separated by the separation portion and to discharge a supernatant of the lubricating oil into the storage portion is disposed between the separation portion and the storage portion.
 2. The compressor according to claim 1, wherein the trap member has a portion rising toward the separation portion, the rising portion having at least one small hole for allowing the supernatant of the lubricating oil to pass therethrough.
 3. The compressor according to claim 2, wherein the trap member is formed of a hat-shaped partition wall.
 4. The compressor according to claim 3, wherein the trap member has a communication hole which communicates the separation portion with the storage portion at a center portion of the trap member.
 5. The compressor according to claim 3, wherein a flange portion having an annular shape extending radially outward from an upper portion of the trap member is formed integrally to the upper portion of the trap member. 